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Our new forecasts show Japanese knotweed will be brought under control by 2040

Our new forecasts show Japanese knotweed will be brought under control by 2040


The latest research by Environet, published this week, shows that due to mortgage lenders’ strict requirements that Japanese knotweed infestations are professionally dealt with in order for a property to be purchased, the UK’s most invasive plant will be brought under control by 2040.

Mortgage lenders will only offer loans on properties affected by knotweed if a professional treatment plan is in place with an Insurance Backed Guarantee lasting five or ten years.

Even if a property is bought without a mortgage, it is a legal requirement that the seller discloses if knotweed is present when completing the Law Society’s TA6 conveyancing form. If they are unaware or fail to disclose the problem, there is an additional safety net in the form of surveyors, who should identify knotweed during a survey, prompting a treatment plan to be put in place so the sale can proceed.

Approximately 1,224,000 homes are sold each year in the UK, forcing those affected by knotweed to tackle the problem. This means Japanese knotweed will be brought under control within 22 years, or by 2040.

Of course, new cases will arise during that time and knotweed will continue to encroach on residential areas from public land such as verges and parks, riverbanks and railways, but increasingly landowners such as Network Rail are being forced to take action to prevent knotweed from spreading into homes and gardens. Therefore, we confidently project that the rapid spread of knotweed across the UK will be under control by that point assuming mortgage lending requirements are not altered.

Nic Seal, Founder and MD of Environet who carried out the research, said, “The problem of Japanese knotweed has only been confronted by lenders in the last decade, meaning that firms are currently still dealing with a huge backlog of affected properties. However, the normal churn of around 4.5% of UK properties coming to market every year means that by 2040, the vast majority of UK housing stock will have been sold at least once and any knotweed infestations should have been tackled.”

A Parliamentary Inquiry is currently underway by the Science and Technology Committee, to investigate the impact of Japanese knotweed on the built environment and whether current mortgage lending decisions are based on sound scientific evidence. The Inquiry is expected to publish its findings in the next few weeks.

Any significant changes to guidelines for lenders by the Royal Institute of Chartered Surveyors could jeopardise our forecast and put homebuyers at risk, so we hope to see the current guidelines reinforced.

If you would like more information about buying and selling properties affected by Japanese knotweed, please visit our advice page which explains exactly what to do to ensure your transaction completes smoothly.

Robert Spaceman

“We had a large stand of bamboo removed, thinned, contained and replaced. The customer service has been first class. Joe and Jason were fabulous and kept me well informed at all times”.